Most people don't know this, but over 425 shellmounds can be found throughout the greater Bay Area, evidence of the Ohlone Indian's once-extensive influence in the region. A local site can be found at Coyote Hills, an East Bay Regional Park in Fremont. But just what is a shellmound?

Unlike arrowheads or earthen pottery, however, not much is known about these hillocks said Ohlone descendant Andrew Galvan. "It's a controversy to some," he said. Known in archeological circles as "midden," shellmounds are essentially mounds of discarded shellfish casings, animal remains, and other organic matter, including human bones. Over time, these bits and pieces build up to become heaps of dirt, and end up as a rise in an otherwise level field. These small hills dot the landscape on both sides of the Suisin Marsh northeast of Martinez, CA.

Shellmounds are not unique to the San Francisco By Area, as similar landmarks have been found from New York to Florida, from the banks of the Mississippi to Seattle. Yet these local remains are the best proof of Ohlone culture. They have been documented to be over one hundred years old according to carbon dating, said Galvan, and were used as burial grounds for a long time by some regional tribes.

In the 1950s and 1960s, San Jose State University, Stanford, UC Berkeley and Cal State Hayward (now Cal State East Bay) conducted archeological excavations of previously undiscovered Bay Area locations. One such dig was in the Coyote Hills area, known as "Tuibun." It is significant because at the turn of the 19th century, over 100 Ohlone Indians were baptized by the padres and priests at Mission San Jose- and most of those Indians listed their home village (address) as Tuibin.

Growth of the shellmounds was not due to unsanitary conditions of the natives, though. "There was no BFI to haul away garbage 2,000 years ago," Galvan asserted. "So they threw their trash in [one pile], away from the village." According to Galvan, after hundreds of years, one particular location would get too crowded, and a new spot would be chosen- successive generations would forget where the previous shellmound was, and the cycle of mound-building would start again.

Some activists, including Ohlone descendants, see the shellmounds as "sacred sites," due to the prevalence of human remains and proximity to former villages. According to www.muwekma.org, a community website of an Ohlone tribe, some people believe that the lands formerly inhabited by Ohlone Indians should be repatriated, including the shellmound areas. Galvan insists it's not a widespread belief, and that the shellmounds are a combination of sites, and not necessarily "sacred." He said, "It's open to interpretation."

From 1908 to 1910, a scholar named Nells Nelson walked around the bay, going from Pinole to Berkeley, from Oakland to Fremont, from Milpitas to Mountain View. Counting the remains of Indian villages as he went, his circumnavigation of the Bay Area resulted in an estimate of no less than 400 separate native settlements, each with its own distinctive shellmound.Several other books have been written about Bay Area shellmounds. One, "A Time of Little Choice," published in 1995 by Randall Milliken, is the "definitive" guide to local villages and Ohlone history. Anrdes Cirdel, a film maker at UC Berkeley, made a movie about a shellmound in Emeryville.

Shellmounds are a welcome part of an effort in recent decades to shed light on the hidden histories of Native Americans. Eventually, with advances in X-ray scanning machines and archeological technology, there will be no need to shovel through the controversial shellmounds, and everyone will be able to see into the past with little disruption. For the time being, however, nothing beats a personal visit to the mounds themselves.

"I've done programs out of Coyote Hills for over 25 years," said Galvan. "I'm excited to take students of any age to that particular location." Whether it's a field trip conducted by the East Bay Regional Park District naturalists or a historical narrative by Ohlone descendants, you can be sure to learn even more about the Bay Area's former residents and their rich heritage.

For more information on guided tours of the Ohlone shellmound, call (510) 795-1683 or visit www.ebparks.org